Battery eliminator



Jan. 7, 1930.

' R. F. BEERS v 1,742,682

BATTERY ELIMINATOR Filed May 18, 1925 I Patented Jan. 7, '1930 UNITED STATES PATENT OFFICE ROLAND F. BEERS, OF BINGHAMTON, NEW YORK, ASSIGNOR TO RAYTHEON INC., OF CAMBRIDGE,.MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS BATTERY ELIMINATOR Application sied may is,

This invention is a novel improvement in rectifying systems, and the principal object thereof is to provide a unit adapted tobe used for supplying direct current of unvarying magnitude, and at multiple and variable voltages, from the ordinary alternating current electric light socket, to radio receivers, am-

. plifiers, loud-speaking telephones, electromagnetic repoducers, telephone or telegraph systems, time clocks,lrelays, or any other electric receptive devices utilizing direct current. Heretofore, 'radio receivers and the like,

employing multiple electrode vacuum tubesv for the detection and amplification of radio signals, have depended for their power upon dry-batteries, storage-cells, or Yso-called battery eliminatorsf" The inherent objections to the use of batteries and cells are numerous, and include the inconvenience, odors,

and spilling of the electrolyte, as wellas the constant wearing down of the batteries necessitating their vre-charging or re laceinent. A number of radio devices have een marketed called battery eliminators, their function being to rectify and filter the usual 110 volt alternating electric light current, obtained from the usual light sockets, and to apply it to the anodes of two or three electi'ode tubes. The main objection to the present types of battery eliminators is the production of a hum in the receivers or loud .speakers of the radio sets, and hence these devices have usually .been limited to replacing the B batteries only, their power rating being very low. Other objections to the usual battery eliminators prevent their widespread use in entirely replacing radio batteries.

Further objects of my :invention are to provide a unit adapted to supply direct cur rent at proper voltages and aniperages to the anodes of multiple electrode vacuum tubes; to supply direct current at proper voltages and amperages to the filamentary cathodes of multiple electrode vacuum tubes; to performv the, two preceding acts without impairing the quality of the radio reception or am lification by the presence of any hum cause by the alternating current generators; to perform the above acts with'a 1925. Serial No. 31,082.

certain degree of independence from the character of the alternating current light socket supply (i. e. with regard to change in line voltage, phase, and frequency) and to possess a degree of adaptability that will permit its use on any type of radio receiver, speech or radio amplifier, tele hone or electromagnetic reproducer, telep one or telegraph system, time clock system, relay, or the like. Another object is to provide one or more sources of rectified current in which potential disturbances arising either kwithin or external to thesupply transformer have no resulting-effect in the source.

Still further objects ofthe invention are to provide a unitwhich maybe used as a B battery supply, i. e., a unit to supply direct current up to 200 milliamperes at voltages ranging from 0 to 500 volts; or may be used as an A battery supply, delivering direct current up to 10 amperes, at voltages from 0 to 50 volts; or may be used as a combination.

enable others skilled in the art to adopt and use the same, and will summarize in the claims the essentials of the invention, the novel features of construction, and the novel combinationsjof parts, for which protection is desired.

In the drawings:

Figure 1 is a diagrammatic view of my rectifying unit including a filter arrangement;

Figure 2 illustrates the manner of winding the transformer and bringing out the leads;

Figure 3 is a bridge showing the relation between the various capacities to produce a balance while Figure 4 is a plot of the conventional B-H magnetization curve.

i Referring to Figure l, it will be noted that the unit comprises two separate and distinct systems the upper being designed to furnish energy of high voltage and low amperage for use in the plate circuit of a thermionic amplifying arrangement while the lower system is adapted toenergize the ilamentary circuit of the amplifier giving a relatively low potential but high am erage within the limits set by the tube rect` ers.

P1 and P2 represent two primaries arranged in series and having applied across the inner terminals the usual 110 volt alternating current supply. The secondary consists of two groups of inductors each containing four coils, making eight in all for a complate A and B potential supply.

As will be apparent, the number of turns in cach coil depends upon the individual load, in members 1 and 2 the turn ratio should provide a slight step-up in potential if the power supply is of' the ordinary house voltage since the load is plate energization of the radio set. However, all the remaining coils furnis-h a step-down voltage translation in supplying a load which necessitates a relatively low potential i. e. either the filament of each rectifier or that of the radio set. It will be noted that coils 2 and 6 are wound in a direction opposite to coils 1 and 5 respectively for the reason to preserve proper polarity of the rectifierl anodes giving the effect of two valves in parallel over a portion of cycle for each load centering in the amplifier.

The outer terminals of coils 1 and 2 are Y joined by an equipotential conductor from whence connection is taken by lead D to one side of the amplifier load; the inner terminals provide potential for the opposite sets of plates in rectifier 10, current passing through conductors C and E. The extreme terminals of coils 3 and 4.- are oined together to form the other side of the amplifier load circuit, while the inner terminals are in electrical connection with the cathode of rectifier 10 through resistors 12 and 13. For regulating the degree of filament incandescence Iutilize duplex rheostat 14 operating to alter simultaneously the resistances in each leg of the cathode circuit; this resistance is effective in maintaining constancy of potential across the outgoing, lines if the alternator voltage changes. The lower group of coils consisting of members 5, 6, 7 and 8 have thesame secon ary connections with respect to rectifier 11 and its specific load as was explained in regard to the upper group. From the foregoing 'zt will be understood that the secondary leads resolve themselves into as many groups of threes as there are immediate loads, the groups being taken directly from the midposition of each pair of coils. Referring now to Fig. 2, I show diagrammatically, the

' manner of winding the coils to effect capacity balance between the different windings and effective ground. While the turn ratio of the transformer in Figure 1 is other than unity, l propose to show for clearness a 1: 1 relation in Figure 2. On core 15, which may be of the shell type I wind the primary in two sections between fianges 16 of a spool made of insulating material, as vulcanite, ebonite and the like, having central partition 17 of a conshield, after which a second metallic shield is wrapped about the firstgroup of secondaries to form a support for the next layer of windings. This group S1 and S2 may be either coils 1 and 2, or 3 and 4, or 5 and 6, or 7 and 8. Then another group of coils S1 and S2 is wound over the first group after the shielding has been put into place. In case onl one rectifier with four secondaries were to e used, as lfor example, the top part of Figure 1, P2 would be divided into two parts o n the same idea as P1 and P2 are divided up and thenS1 and S2 of each grou would be woundon. The shielding 18 is, o course, grounded to 17 and the outer casing. The transformer in its final form comprises a number of coil pairs concentrically mounted, each coil of a pair being separated by the partition while the pairs are electrostatically shielded from one another by the metallic layers. The number of pairs of coils correspend to the. several loads which in the case of filament and plate energization as shown in Figure 1 would necessitate four. It will be seen that if the coils have been wound symmetrically on the spool, tlie leads terminating the primary and each pair of secondaries will be equidistantly disposed with respect to separator 17 and the end portions of the core. In view of the fact that distributed capacity of the windings may be considered as operating at the ends of thecoils in the form of lump capacity, the effect of capacity to ground as represented by the core and middle separator may be diagrammatically indicated by elements C1 C203 C4 C5 C6 C7 and C2. Thus it will be seen thatin its broader aspects, my invention has for one of its results-the Winding of a transformer in such a way that each coil is so related electrostatically to the remaining coils that outside disturbances effecting one, tend to effect all and are balanced out. This requires the primary to be in at least two parts and composing half of the bridge and two secondaries composing they other half of the bridge. In this way, line disturbances are symmetrically distributed in 'such a way that they are cancelled within the transformer. Of course, S1 and S2 in the bridge in Figure 3 may be considered to either represent all S1' coils and all S2 coils collectively, or those coils individually. In that case, there will be just as many bridges as .loads because with respect to there are S1 "coils, but all those bridges will be so related to each other that disturbances from the line willbe cancelled in all of them. In this way, the necessity for buffer condensers across the secondary is reduced, 1f not, eliminated. l

In Figure 3, I have reconstructed the arrangement of windings andtheir capacity equivalent in the form of a bridge. It 1s apparent that ifthe several impedances balance each other in accordance with the properties of the bridge, extraneous disturbances whether of an audio or radio frequency nature causing undulations of potential in the primary or any of the secondaries, produce no deleterious eect across the terminals of the amplifier plate energization and filament these variations points X and Y, representing the relation in the bridge between the equipotential conductors of the primary and each of the secondaries, are at the same potential. another way, the effect of distributed capacity which ordinarily offers a ready path for high frequency variations in potential has been nullified by the specific position of transformer leads with respect to the metallic casing, thus introducing a capacity balance. The latter also functions effectively to necessitate a proper division of load between .both rectifiers. Furthermore, it is apparent that the bridge may consist in capacity to a ground other than that shown for example, between the terminus of the primary and secondary windings and any symmetrically placed surface of zero potential such as the electrostatic shield separating layers. In this case, the ground from whence to derive the necessary balance of impedance is transferred from the core and separator to the concentric cylinders. Duplex rheostat 14 providesI equal changes of resistance in the rectifier filament leads, preserving equality of impedance to maintain the bridge. In view of the network, electrical balance will exist under all conditions of voltage transformation and is applicable to each'and every coil pair symmetrically wound on the same core. For rectifiers 10 and 11, the heated cathode type containing two electrodal elements is preferred although I illustrate a conventional three electrode device in which the grid and plate members are connected together to form an anode of comparatively large area; this form of tube is available in the market. All types of rectifiers including gaseous conduction between solid electrodes and electrolytic devices, yielding an order of voltage and current demanded by the load are adapted to my system. However it is obvious that the number of pairs of coils should be modified to accommodate the particular form-.of unilateral conductor utilized. From each rectifying unit, the current passes through filter F to the ultimate load which in the upper system,

Stated in l comprises plate energization of an amplifying arrangement. If desired, a otential of lower order for a'detector may e obtained by including structure indicated by adjustable resistance 19 to produce the necessary potential drop. The voltage applied across the plates of the amplifier may be regulated by rheostat 14 or in any manner known to the art. All forms of low pass filters may be employed; the type illustrated comprises scries choke and shunt condensers. In the lower system, rheostat 20 for regulating the current passing the amplifier cathode load is connected preferably in series with the outgoing line.

As .an expedient for preventinen changes in voltage due to poor regulation o? the alternator, I propose to operate the core of the transformer either at the lower or the upper bend ofthe magnetization curve app cable tothe particular core material. Referring now to Figure 4 it will be apparent that if either of the points A and A are selected by controlling the terminal voltage of the alternator or by properly dimensioning the cross-section of core to produce a particular root mean square value of flux density,

proportional changes in magneto-motive.

force do not yield corresponding variations in flux due to the decrease in slope of curve at the chosen positions. However, it is preferable to operate at the upper .bend for economic reasons.

If desired, the transformer or any part thereof may be placed within a case of conducting material as steel, to prevent leakage flux from adversely affecting the remaining apparatus.

In view of the foregoing it will be apparent that the upper and lower rectifying systems may each be fed from individual transformers and utilized in the manner shown as a combined source of filament and plate energization for a radio system or singly for either of the energization purposes. y

I do not limit'my invention to the exact forms shown in the drawings, for obviously changes may be made therein within the scope of the claims.

I claim:

1. In a rectifying system comprising an input circuit subject to extraneous disturbances, an output circuit, a transformer disposed between circuits and including a caaffect said output, the methgether, the leads from the inner terminals being brought out from the mid-point of each pair toA form with said imepdance a balanced electrical bridge.

3. In combination, the following: a source of alternating current, a direct current load that demands high constancy `of potential, a rectifier and transformer disposed therebetween having primary and secondary wind- .and a double unit rectifier ings sectionized to form inner and outer termmals, equipotential conductors joining the last-mentioned terminals, the primary and secondary inner terminals passing to said sourceand rectifier respectively.

4. In combination, a source of alternating current subject to potential disturbances, a direct current load that demands high constancyofpotential,a rectifier and transformer disposed therebetween having primary and secondary windings with distributed capacity and a metallic shield between windmgsjo form with the distributed capacity a r1 dge whereby the disturbances are precluded from affecting the load.

5. In combination, a source of alternating current, a direct current load, a transformer disposed between said source and load and in conjunction 4with the capacity inherent in the transformer windin for maintaining the pro r division of Ida umts of sai rectifier. l

6. Ina rectiing system comprising an input circuit su ject to extraneous disturbances, an output circuit, a transformer includ-V mg capacity; coupling between windings vwhereby the disturbances affect the output circuit, the method which consists in introducing and roportioning capacity effects in the trans ormer with respect to ground to form with the coupling capacity av balanced network.

7. In a rectifying system, comprising an input circuit sub'ect to voltage disturbances,

, an output circuit, a transformer including capacity couplingbetween windings whereb the distur ances affect the output circuit, t e method which consists in utllizin capacity effects in the transformer wit respect to ground to form with the coupling capacity a balanced network and in operatmg the transformer core at a relatively high 'flux densit whereby the disturbances are prevented om assmg tothe ouput circuit. In testimony t at I claim the foregoing as my own I aix my si ature.

LAND BEERS.

means. operating d between the the 

